The volume reviews the state of the art in the developing field of risk assessment and provides some risk assessment for drinking water exposure to 14 compounds of interest to the EPA as the agency develops its regulatory program. Reflecting the tendency of past toxicological studies to focus on cancer as the main health effect of concern, most of the risk assessments in the report were estimated for carcinogenicity. Wherever data were adequate, however, the committee also developed risk assessments for noncancer end points. The report assesses methods for using epidemiological data in conducting risk assessments and methods for extrapolating results of laboratory animal inhalation studies to estimate human risk from ingestion. The reports describes mathematical modeling approaches currently available or under development of the assessment of noncancer risks.